Today's advanced miniature wireless communication devices are equipped with miniature antennas. To broaden frequency band width of communication channel, not only the selected antenna frequency is therefore gradually broadened than ever, but also high frequency (HF) radio frequency (RF) communication channels are shared by the advanced miniature communication devices. For example, Bluetooth protocol is implemented to a various products requires a broad bandwidth in the 2.4 GHz band, while users of global system for mobile communications (GSM) roam requires 1.8 GHz band, but applications for wireless local area network (WLAN) can be selectively worked with the release of standard 2.4 GHz and faster 5.2 GHz dual band.
Conventional laptop computers are usually equipped with built-in antennas to process 2.4 GHz signals connected to internet due to a limited inner space, but it could not process 5.2 GHz signals connected to cable television. External antennas are necessitated to provide dual band signal strength. At the same time, personal digital assistant (PDA), palm television services (Palm TV) are also added with external antennas for connecting to cable television.
As shown in FIG. 1, a rear end of a conventional electronic device (4) (i.e. laptop computer) are equipped with two signal sockets (41, 42), one is a standard band signal socket (41) accessing for a first channel (for example, 2.4 GHz band), the other is a broad band signal socket (42) accessing for a second channel (for example, 5.2 GHz band). The standard band signal socket (41) is connected to a wireless antenna (6) for transmitting and receiving wireless signals to the electronic device (4) accessing for the internet. The broad band signal socket (42) is connected to a plug (50) of an external antenna (5) for transmitting visual signals to the electronic device (4) accessing for the cable television (TV). When the wireless antenna (6) is applied for transmitting data on line, the external antenna (5) is out of use. Conversely, when the external antenna (5) is applied for transmitting cable TV signals, the wireless antenna (6) is out of use.
Or the electronic device (4) has a built-in antenna accessing for the internet as the first channel; while the plug (50) of the external antenna (5) fits into the signal socket (42) accessing for the cable TV instead, or the plug (50) idly draws out of the signal socket (42) on the rear end of the electronic device (4).
Since rear end of the conventional electronic device (4) is custom prefabricated with two signal sockets (41, 42) accessing for dual channel, the limited inner space is crowded to accommodate two signal sockets (41, 42). It may cause signals crosstalk etc. Therefore, if two signal sockets can be integrally incorporated into only one signal socket, further dual channel being provided therewith invoke aid of a compact design with improving space utilization for the electronic device.
Furthermore, a built-in antenna as well as an external antenna (5) incorporated into the conventional electronic device (4) may fail to match selected frequency but weaken signal strength due to they are crowded inside the limited inner space of the electronic device (4). The present invention is to provide a collapsible antenna added with external adapter to improve the problems as mentioned above.